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Old 19th August 2005, 01:41 PM   #11
jaycee is offline jaycee  United Kingdom
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just want to hear general opinions about it
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Old 19th August 2005, 02:48 PM   #12
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lots of meaningful points.

Does the source (manufacture) matter for 5534? TI is the best? Or no need to care that. I find that NJR 5534 is much cheaper than TI 5534.
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Old 19th August 2005, 06:58 PM   #13
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I think they're best used for low (<10) inverting gain and low (<10k) source impedances, if you need high noninverting gain with high quality for phono preamps then OPA627/637 is worth the extra cost.

NE5534 and LM318 are the only op amps I know of that bring out the collector terminals of the 1st LTP stage (Pins 1,8), this lets you add a discrete 1st LTP stage without added phase shift, also the 5534 comp pin (pin 5) can be used with 5 - 10mA current source for a class A CFP output stage that bypasses the on-chip short-circuit protection, refer to this post, this post, and the schematic in this 5534 datasheet.
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Old 19th August 2005, 07:26 PM   #14
mikeks is offline mikeks  United Kingdom
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Quote:
Originally posted by klitgt

Lovers say NE5534 is much more musical than FETs.
If it's 'musical', then i don't want it....!

...amps must never be 'musical'....

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Old 19th August 2005, 07:42 PM   #15
tlf9999 is offline tlf9999  United States
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Quote:
Originally posted by nuvistor
Ialso the 5534 comp pin (pin 5) can be used with 5 - 10mA current source for a class A CFP output stage that bypasses the on-chip short-circuit protection,
Why do you have to spill out all the secrets about this wonderful chip?

That has been the single biggest advantage (for me anyway) of this particular design. It saves you time and effort to design your own input+VAS.
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Old 19th August 2005, 08:12 PM   #16
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Quote:
Does the source (manufacture) matter for 5534?
In my experience Texas Instruments 5534 sounds 'grey' in comparison with the Philips, the latter sounding fuller and more colourful. Despite its shortcomings I find it has an attractively open and unforced sound.

Tim.
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Old 19th August 2005, 08:13 PM   #17
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Quote:
Why do you have to spill out all the secrets about this wonderful chip?
I've known about the 1st stage trick for almost 25 years, but I have to admit that I didn't understand that the 5534 output stage was NPN totem pole and that you could sink significant current from pin 5 before last year, after poring over its schematic for probably the 50th time. Hopefully others can enjoy this knowledge.

If you have noninverting gain you really should try the 1st stage trick, with cascoded matched dual JFETs if you can, or matched NPN with emitter resistors. IME almost as good as an OPA627 and much better than the 5534 for clarity, and the reduced OL gain allows unity gain without added Ccomp.
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Old 19th August 2005, 09:18 PM   #18
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Several years ago I was quite amazed, that the input stage of that NE5534 has massive head room.
I measured this, when "discovering" TIM distorsions due to
overdrive events of the input stage. Under normal conditions
the input stage only uses a small percentage of it max. swing.
(If I remember right: I measured the signals pin 1 & 8 at 10kHz sine wave 10V out put and found that it used only 20% of its clipping limit.
So it really needs bad HF steps in the audio signal to overwhelm this
old timer OpAmp).
I found this quite amazing, because you get principally more noise the more head room you spend there... and noise of that beast is also fine!
I tried to compare this with the higher graded OP37 that times and
TL072, but Ne5534 seemed to be outstanding.
Also my ears found them OK.

...would be interesting to compare them with some more
modern OpAmps like AD8610 / AD8620....
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Old 19th August 2005, 09:50 PM   #19
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Interesting comments on input stage headroom. You don't mention feedback network configuration, assuming unity-gain follower with 22pF Ccomp and 10kHz input, 5534 has Avol of 60dB, input stage gain is 13k/(0.026/200uA) or 100, so 2nd + 3rd stage gain is 10, and voltage on pins 1,8 would be 10V/10 or 1V. IOW the negative feedback reduces the 1st stage voltage swing by the available Avol and the closed loop gain Acl, more Avol and less Acl will reduce the swing.
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Old 19th August 2005, 10:16 PM   #20
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Quote:
Originally posted by nuvistor
Interesting comments on input stage headroom. You don't mention feedback network configuration, assuming unity-gain follower with 22pF Ccomp and 10kHz input, 5534 has Avol of 60dB, input stage gain is 13k/(0.026/200uA) or 100, so 2nd + 3rd stage gain is 10, and voltage on pins 1,8 would be 10V/10 or 1V. IOW the negative feedback reduces the 1st stage voltage swing by the available Avol and the closed loop gain Acl, more Avol and less Acl will reduce the swing.
...urghs, should have documented that, but I didn't.
The set up was a higher gain non inverting amp (Feedback 2k2 and
100 Ohms from inv input to ground.... or something like that....)
I used no Ccomp.
From my understanding the signal on pin 1 & 8 at stable 10khz sinewave is determined by the output swing and the gains between output and collectors of the input stage.
Some of these gains have f3-corners much below 10kHz, so with increasing frequency the input stage will have to deliver more signal to achieve a constant magnitude at the output of the OpAmp....
For rectangular input signals you will get massive peaks at the input and collectors of the input stage as the OpAmp output will slope slower and less signal feed back. Means higher error signal and with this massive regulation action. The peaks at the collectors of the input stage are not uncontrolled overshoots, it's a proper error correction. .... well, it is proper as long as the input stage does not clip...
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